ALBERT

Beschreibung: We perform a multi-scale impact assessment of tephra fallout and dispersal from explosive volcanic activity in Iceland. A companion paper (Biass et al., 2014) introduces a multi-scale probabilistic assessment of tephra hazard from 4 Icelandic volcanoes (Hekla, Askja, Eyjafjallajökull and Katla) and presents probabilistic hazard maps for tephra accumulation in Iceland and tephra dispersal across Europe. Here, we present the subsequent vulnerability and impact assessment, that accounts the relevance of single features at national and European levels and considers several vulnerability indicators for tephra dispersal and deposition. At national scale, we focus on physical, systemic and economic vulnerability of Iceland to tephra fallout, whereas at European scale we focus on the systemic vulnerability of the air traffic system to tephra dispersal. Results include vulnerability maps for Iceland and European airspace and allow identifying the expected impacts of the different eruptive scenarios considered. Results at national scale show that tephra accumulation from the considered eruptive scenarios can disrupt main electricity network, in particular in case of eruption at Askja volcano. Results also show that if eruptive scenarios occurred at Hekla, Askja and Katla volcanoes, many power plants would be affected, causing a substantial systemic impact due to their importance for the Icelandic economy. Moreover, the considered scenarios at Askja and Katla could produce substantial impact on agricultural activities (crops and pastures). At European scale, tephra dispersal from explosive volcanic activity at Askja and Katla volcanoes is likely to produce substantial impacts at European level and, in particular, at Keflavik and London Flight Information Regions (FIRs), but also at FIRs above France, Germany and Scandinavia, in particular for long-lasting activity at Katla volcano. Explosive activity at Hekla volcano is likely to produce high impacts at Keflavik FIR and London FIRS, but in case of higher magnitude scenario, can impact also France FIRs. Results could support land use and emergency planning at national level and risk management strategies of the European air traffic system. Although we focus on Iceland, the proposed methodology could be applied to other active volcanic areas, enhancing the long-term tephra risk management.

Beschreibung: In order to assist the elaboration of proactive measures for the management of future volcanic eruptions in Iceland, we developed a new scenario-based approach to assess the hazard associated with tephra dispersal and sedimentation at various scales and for multiple sources. The target volcanoes are Hekla, Katla, Eyjafjallajökull and Askja, selected either for their high probabilities of eruption and/or their high potential impact. By coupling tephrostratigraphic studies, probabilistic techniques and modelling, we developed comprehensive eruption scenarios for both short- and long-lasting eruptions and compiled hazard maps for tephra ground deposition at a national scale and air concentration at a European scale using the TEPHRA2 and FALL3D models, respectively. New algorithms for the identification of realistic sets of eruptive source parameters are investigated, which assist the generation of probability density functions of eruption source parameters for the selected scenarios. Aggregation processes were accounted for using various empirical models. Outcomes, i.e. probabilities conditioned to the occurrence of an eruption, help the assessment and comparison of hazard levels at different scales. For example, at a national scale Askja has a 5–10% probability of blanketing the easternmost half of the country with a tephra accumulation of at least 1 kg m−2. At a continental scale, Katla has a 5–10% probability of producing ash clouds with concentrations of 2 mg m−3 over the UK, Scandinavia and northern Europe with a mean arrival time of 48–72 h and a mean persistence time of 6–18 h. In a companion paper, Scaini et al. (2014) present a vulnerability assessment for Iceland to ground deposition of tephra and for the European air traffic to airborne ash which, combined with the outcomes of the present paper, constitute one of the first comprehensive multi-scale risk assessment associated with tephra dispersal and sedimentation.

Beschreibung: In order to assist the elaboration of proactive measures for the management of future volcanic eruptions in Iceland, we developed a new approach to assess the hazard associated with tephra dispersal and sedimentation at various scales and for multiple sources. The target volcanoes are Hekla, Katla, Eyjafjallajökull and Askja, selected either for their high probabilities of eruption and/or their high potential impacts. By coupling tephrostratigraphic studies, probabilistic techniques and modelling, we developed comprehensive eruption scenarios for both short and long lasting eruptions and compiled hazard maps for tephra ground deposition at a national scale and air concentration at a European scale using the TEPHRA2 and FALL3D models, respectively. New algorithms for the identification of realistic sets of eruptive source parameters are investigated, which assist the generation of probability density functions of eruption source parameters for the selected scenarios. Aggregation processes were accounted for using various empirical models. Outcomes help assessing and comparing hazard levels at different scales. For example, at a national scale Askja has a 5–10% probability of blanketing the easternmost half of the country with a tephra accumulation of at least 1kg m-2. At a continental scale, Katla has a 5–10% probability of producing ash clouds with concentrations of 2 mg m-3 over the UK, Scandinavia and northern Europe with a mean arrival time of 48–72 h and a mean persistence time of 6–18 h. In a companion paper, Scaini et al. (2014) present a vulnerability assessment for Iceland to ground deposition of tephra and for the European air traffic to airborne ash which, combined with the outcomes of the present paper, constitute one of the first multi-scale risk assessment associated with tephra dispersal and sedimentation.

Beschreibung: We present a detailed chronological reconstruction of the 2011 eruption of Puyehue-Cordón Caulle volcano (Chile) based on information derived from newspapers, scientific reports and satellite images. Chronology of associated volcanic processes and their local and regional effects (i.e. precursory activity, tephra fallout, lahars, pyroclastic density currents, lava flows) are also presented. The eruption had a severe impact on the ecosystem and on various economic sectors, including aviation, tourism, agriculture, and fishing industry. Urban areas and critical infrastructures, such as airports, hospitals and roads, were also impacted. The concentration of PM10 (Particulate Matter ≤ 10 μm) was measured during and after the eruption, showing that maximum safety threshold levels of daily and annual exposures were surpassed in several occasions. Probabilistic analysis of atmospheric and eruptive conditions have shown that the main direction of dispersal is directly towards east of the volcano and that the climactic phase of the eruption, dispersed toward south-east, has a probability of occurrence within 1 %. The management of the crisis, including evacuation of people, is discussed, as well as the comparison with the impact associated with other recent eruptions located in similar areas and having similar characteristics (i.e. Quizapu, Hudson, and Chaitén volcanoes). This comparison shows that the regions downwind and very close to the erupting volcanoes suffered very similar problems, without a clear relation with the intensity of the eruption (e.g. health problems, damage to vegetation, death of animals, roof collapse, air traffic disruptions, road closure, lahars and flooding). This suggests that a detailed collection of impact data can be largely beneficial for the development of plans for the management of an eruptive crisis and the mitigation of associated risk of the Andean region.

Beschreibung: In this paper we present a probabilistic hazard assessment for tephra fallout at Mt. Etna (Italy) associated with both short- and long-lived eruptions. We analyzed wind data from the atmospheric soundings of the Italian Air Force at Trapani Birgi (western Sicily), and use the TEPHRA advection-diffusion-sedimentation model to capture the variation of wind speed and direction with time. Two different typologies of eruptions were considered in our analysis: eruptions forming strong short-lived plumes (SSL eruptions) and eruptions forming weak long-lived plumes (WLL eruptions). One Eruption Scenario (OES) for both typologies and the Eruption Range Scenario (ERS) for WLL eruptions were identified based on well documented past activity of Etna since the '90. First, model calibration was carried out for two well-known Etna explosive eruptions: the 22 July 1998 and July 2001 Etna eruptions. Second, probabilistic maps were compiled. Results clearly show that the eastern flanks are significantly affected by tephra deposition and that the WLL eruptions and the Plinian eruption of 122 BC represent the largest threat for both infrastructures and agriculture.

Beschreibung: We perform a multi-scale impact assessment of tephra fallout and dispersal from explosive volcanic activity in Iceland. A companion paper (Biass et al., 2014; "A multi-scale risk assessment of tephra fallout and airborne concentration from multiple Icelandic volcanoes – Part I: hazard assessment") introduces a multi-scale probabilistic assessment of tephra hazard based on selected eruptive scenarios at four Icelandic volcanoes (Hekla, Askja, Eyjafjallajökull and Katla) and presents probabilistic hazard maps for tephra accumulation in Iceland and tephra dispersal across Europe. Here, we present the associated vulnerability and impact assessment that describes the importance of single features at national and European levels and considers several vulnerability indicators for tephra dispersal and deposition. At the national scale, we focus on physical, systemic and economic vulnerability of Iceland to tephra fallout, whereas at the European scale we focus on the systemic vulnerability of the air traffic system to tephra dispersal. This is the first vulnerability and impact assessment analysis of this type and, although it does not include all the aspects of physical and systemic vulnerability, it allows for identifying areas on which further specific analysis should be performed. Results include vulnerability maps for Iceland and European airspace and allow for the qualitative identification of the impacts at both scales in the case of an eruption occurring. Maps produced at the national scale show that tephra accumulation associated with all eruptive scenarios considered can disrupt the main electricity network, in particular in relation to an eruption of Askja. Results also show that several power plants would be affected if an eruption occurred at Hekla, Askja or Katla, causing a substantial systemic impact due to their importance for the Icelandic economy. Moreover, the Askja and Katla eruptive scenarios considered could have substantial impacts on agricultural activities (crops and pastures). At the European scale, eruptive scenarios at Askja and Katla are likely to affect European airspace, having substantial impacts, in particular, in the Keflavík and London flight information regions (FIRs), but also at FIRs above France, Germany and Scandinavia. Impacts would be particularly intense in the case of long-lasting activity at Katla. The occurrence of eruptive scenarios at Hekla is likely to produce high impacts at Keflavík FIR and London FIRs, and, in the case of higher magnitude, can also impact France's FIRs. Results could support land use and emergency planning at the national level and risk management strategies of the European air traffic system. Although we focus on Iceland, the proposed methodology could be applied to other active volcanic areas, enhancing the long-term tephra risk management. Moreover, the outcomes of this work pose the basis for quantitative analyses of expected impacts and their integration in a multi-risk framework.

Beschreibung: In this paper we present a probabilistic hazard assessment for tephra fallout at Mt. Etna (Italy) associated with both short- and long-lived eruptions. Eruptive scenarios and eruption source parameters were defined based on the geological record, while an advection–diffusion–sedimentation model was used to capture the variation in wind speed and direction with time after calibration with the field data. Two different types of eruptions were considered in our analysis: eruptions associated with strong short-lived plumes and eruptions associated with weak long-lived plumes. Our probabilistic approach was based on one eruption scenario for both types and on an eruption range scenario for eruptions producing weak long-lived plumes. Due to the prevailing wind direction, the eastern flanks are the most affected by tephra deposition, with the 122 BC Plinian and 2002–2003 eruptions showing the highest impact both on infrastructures and agriculture.